Relationships between fine memory discrimination and tau burden in two independent cohorts of older adults.

Poorer fine memory discrimination on the MST was associated with higher tau PET burden in the A4 cohort of cognitively normal, amyloid-positive older adults.

• A4 cohort: N=407, 59% female, mean age=71.66, age range=65-85
• Participants were cognitively normal and amyloid-positive, drawn from the Anti-Amyloid Treatment in Asymptomatic Alzheimer's (A4) study
• Tau was assessed using PET imaging
• The study design was cross-sectional using baseline data

Poorer fine memory discrimination on the MST was associated with higher CSF tau (p-tau181 and total tau) in the EXERT cohort of older adults with amnestic MCI.

• EXERT cohort: N=41, 61% female, mean age=74.10, age range=65-89
• Participants were drawn from the Exercise in Adults with Mild Memory Problems (EXERT) trial
• Both p-tau181 and total tau from CSF were associated with poorer MST performance
• The study design was cross-sectional using baseline data

Poorer fine memory discrimination on the MST was associated with higher amyloid PET burden in the A4 cohort.

• A4 cohort: N=407, cognitively normal and amyloid-positive older adults
• Amyloid burden was assessed using PET imaging
• This association was found alongside the relationship between MST performance and tau PET

Poorer fine memory discrimination on the MST was associated with smaller hippocampal volume in the EXERT cohort.

• EXERT cohort: N=41, older adults with amnestic MCI
• Hippocampal volume was included as an AD-related brain measure alongside CSF tau and amyloid
• This finding was specific to the EXERT cohort; hippocampal volume relationships were explored in both cohorts

Poorer delayed recall on Logical Memory was associated with higher tau and amyloid burden in A4 and with lower hippocampal volume in EXERT.

• Logical Memory is described as a traditional memory test
• In A4, delayed recall was associated with both higher tau PET and higher amyloid PET
• In EXERT, delayed recall was associated with lower hippocampal volume
• Results were compared to MST findings to explore relative sensitivity of the two measures

Poorer retention on Logical Memory was associated with higher tau in Braak I regions and higher amyloid in A4, and with CSF tau and lower hippocampal volume in EXERT.

• Braak I is an early region of tau deposition, consistent with the paper's focus on early tau pathology
• In A4, retention was associated with both Braak I tau and amyloid PET
• In EXERT, retention was associated with CSF tau and lower hippocampal volume
• Retention was examined as a distinct Logical Memory metric separate from delayed recall

The Mnemonic Similarity Task is designed to assess hippocampal integrity and was used as a potential low-cost adjunctive marker of tau pathology in the medial temporal lobe.

• The medial temporal lobe is described as 'an area vulnerable to early tau deposition'
• The MST is described as a 'fine memory discrimination task designed to assess hippocampal integrity'
• The rationale is that cognitive assessments sensitive to medial temporal lobe integrity 'may serve as low-cost adjunctive markers of underlying tau pathology in older adults'
• Both MST and Logical Memory were examined as cognitive markers